A known accumulator fuel injection device pressurizes and pumps high-pressure fuel to a common rail with the use of a fuel supply pump rotated by an engine such as a multi-cylinder diesel engine. The fuel injection device accumulates the high-pressure fuel in the common rail. The fuel injection device distributes the high-pressure fuel, which is accumulated in the common rail, to injectors mounted in respective cylinders of the engine and carries out injection supply of the high-pressure fuel into the combustion chambers of the respective cylinders (for example, as described in JP-A-2001-82230). A fuel injection controller senses fuel pressure in the common rail as actual common rail pressure with a fuel pressure sensor. The fuel injection controller performs feedback control of a fuel discharge quantity of a fuel supply pump to substantially conform the actual common rail pressure to target common rail pressure set based on an operation state of the engine. The fuel injection controller calculates injection pulse width based on a target injection quantity set based on the actual common rail pressure and the operation state of the engine. The fuel injection controller carries out injection quantity control for controlling energization of an injection drive signal of the injector in accordance with the injection pulse width.
However, with the conventional technology, when a characteristic deviation is caused in a sensing signal sensed with the fuel pressure sensor, e.g., because of incorrect wiring of a sensor harness, there is a possibility that the control is performed based on a value shifted from the target common rail pressure. For example, when the actual common rail pressure sensed by the fuel pressure sensor shows a characteristic value shifted to the low pressure side from the actual pressure, the operation is performed at higher pressure than the target common rail pressure. As a result, there is a possibility that the injection quantity injected and supplied from the injector to the engine increases. When the increase in the injection quantity due to the characteristic deviation of the fuel pressure sensor is large, there is a possibility that the aimed engine operation state cannot be maintained.
The present invention has been made by taking such the situation into account and has an object to provide a fuel injection controller capable of determining whether control is normal control or abnormal control based on a sensing signal of a fuel pressure sensor even if a characteristic deviation of the fuel pressure sensor arises due to incorrect wiring or the like.